@article {IOPORT.00428032,
    author       = {\c{T}\^ambulea, Leon},
    title        = {Binary trees, an Euler's problem and finite sequences of numbers.},
    year         = {1990},
    journal      = {Studia Universitatis Babe\c{s}-Bolyai. Mathematica},
    volume       = {35},
    number       = {3},
    issn         = {0252-1938},
    pages        = {83-94},
    publisher    = {Universitatea Babe\c{s}-Bolyai, Cluj-Napoca; Cluj University Press, Cluj-Napoca},
    identifier   = {00428032},
}